minor change in a comment

--HG--
extra : transplant_source : %C8%82%26%AE%B3%95%F5%27%8D%FCxu%40%E7V%E1m%B3%40%DA

gevent/hub.py

@@ -170,7 +170,7 @@ class Hub(greenlet):
         try:
             self.keyboard_interrupt_signal = signal(2, core.active_event, MAIN.throw, KeyboardInterrupt)
         except IOError:
-            pass  # no signal() on windows
+            pass  # no signal() on Windows
         try:
             loop_count = 0
             while True: